Henri chretien



H. CHRTIEN.

COLLIMATING DEVICE AND METHOD 0F SIGHTING.

APPLICATION FILED MAY l. 1919.

'1,3 1 1 846. Patented July 29, 1919.

f lNvENToR HENRI CHIRTIEN, F NICE,

COLLIMATING DEVICE AND METHOD 0F SIGHTING.

Speeicationl of Letters latent.. Patented July 29, 1919.

Application led May 1, 1919. Serial No. 294,077.

` rifles, machine guns, and for other similar purposes.

It has been recognized for a longtime that the method of aiming at a target by means of a system of front and rear si hts is a very unsatisfactory one. This met od, without any theoretical necessity obliges the shooter to place his eye in a sharply deter- `minedposition and to keep it constantly -so while bringing the line of sight in the direction of the target. In such a system it is necessary for the shooter to aline four points before he is ready to fire, namely, the eye, the rear sight, the front sight and the target. Furthermore, on account of the differences in distance between the .eye and the target,the eye and the front sight, and the eye and the rear sight respectively, 4the sight of accommodation of the eye is very unsteady, and this results in very rapid visual fati e. The ultimate consequence of all .these diiiculties is to delay and confuse the act of firing. Y It has heretofore been sought to overcome these diiiiculties, and severalattempts have' been made to that end but none of such attempts has been successful in eliminating all the .difliculties encountered in what appears to be such asimple operation, but which, in

fact, is a Very complicated one. 1

. -It4 has been attempted heretofore to solvev the problem by' usmg asmall, telescope, but

this hasproven to be unsatisfactory in many respects. The use of a vmagnifying instrument, such as the telescopes heretofore used, was probably with a view to increasing the accuracy of sight. This, however, is fallacious and combined with the well known physiologicalV fact that the faculty of accommodation of thel eye islacking when viewing under such conditions, and .therev fore, necessitates v'the individual focusing of the instrument. `The supposed increase in accuracy .by the magnifying power is thus illusory and while aiding and overcoming merous ways involving various devices. The accompanying drawings illustrate the invention in three preferred forms.l AIn' the drawingssome of the difficulties, produces others which are equally objectionable, as for instance, the magnification exaggerates the motions of the gun as shown by the apparent motion. of the target, which somewhat bewilders the observer. It also reduces proportionally both the field view and the diameter of the exit pupil of the instrument in which the pupil of the observers eye is to be placed. Therefore, a more careful adjustment of the position of the eye is necessary, which reduces the promptness of firing.

One of the objects of my invention is to give the most complete solution of all these physiological problems of sight which present themselves when aiming at a very rapidly moving target, possibly an enemy. My invention is most com letely illustrated in' its application to the ght of one aeroplane with another.

The invention consists of an optical device which projects a knownoptical index 0r emblem over the image of the target without substantially impairing the image of the target 'either in' regard to position, slze o r luminosity. By this means the observer 1s enabled'to sight in the most natural manner. He may look with both eyes open directly at the target itself, looking far away into a -to focusupon but the target.

By using the collimator, embodying my invention, the shooter keeps the full control of all his physiolo 'cal powers, is able to judge evolutlons of t e enemy and to fire with maximum promptness because of the unit magnifying power of the instrument.

My invention' may be carried out 1n nuforms of Figure 1 represents one form, namely of a lrectilinear clear collimator (long type).

.' Fig. 2 re resents another form, namely.

of a` rectilinear i clear collimator. (short wget 1g. 3 represents a third form, namely, a clear collimator (catadloptric type); and

Fig. 4 is a section along line 4-4 of. ria y ferring to Fig. 1, 'the instrument there shown is composed of two optical systems A and B, preferabl. identical, although not necessarily so. hese two systems are mounted symmetrically in succession, the

system B' being intended for erecting the image transmitted by the first system, it i being understood that the system A is the front system of the device. The magnifying power of the systems A 'and is not necessarily equal to unity, it being necessary only thatthe magnifying power of the complete system, including systems A and B,- be equal to unity. It is, however, my

preference lfor practical reasons and convenience, that the. component parts ofthe system, that is to say, the systems A and B, shall be identical.

Each of the systems A and B is composed oftwo achromatic lenses having the same power. The system Av has the lenses 1 and 2,

and the system B has the lenses 3 and 4, all of said lenses being placed-in a casing `5. Placed in the focal plane ofthe lens 1 is a surface 6, upon which is engraved or otherwise applied the pattern or emblem of `known configuration, which is to be projected on the target'. This pattern or emblem may consist of a' cross-wire stretched across the field, or any other suitable em- .The lens 2 is placed in such a position that its front focal plane lcoincides with the plane of the pattern or emblem. The lens 2 transmits the image of the target as well as the emblem, but that 'image is also inverted and cannot, therefore, be used for 4the purpose intended. The' second telescopic system, that is the system B, is provided for the sole precedin image transmitted by the. system A. hat is to say, the image comes.in

through. lens 1 and is shown on lens 2 in an inverted* posltion. It is then transmitted bythe lens 3 and shown on the lens `4 in 'an' upright position, that is the same po- -slti'on as itV carne in through the lens 1. In

- point fatl infinity. By proper choice of thel glasses, the 'astigmatism and the curvature` minimum..

metrical optics, the adoption other words, there are means between the Ilensesl and .fg-for erecting the ima'ge.

The .curvature of the surfaces of the lenses issuch as to remove both the chromatic and the' spherical aberration for a of field can hev reduced 4to an acceptable 4From the theoretical standpoint of geol of'a unit magmfication and'of a symmetrical disposition of the 'lenses has many advantages.- The purpose of erecting the- B depends upon the length available for the whole instrument.

When the space available for an instrument, such as that shown in Fig.l 1, is such that it is necessary to reduce Aits length to such an extent that the field would be undesirably reduced, this may be overcome by the device shown in Fig.v 2, which, aside from its length, is the same as the device of Fig. 1, with the exception that in. place of the plane 6, a field lens 9 is inserted, said lens 9 bearing upon its plain surface the known pattern' or emblem.` The device of Fig. 2` also has placed therein between the lenses corresponding to the lenses 3 and 4, a field lens 10 instead of the diaphragm 8, as in Fig. 1.

It will be noted also that in Fig. 2 the two internal lenses corresponding to the lenses 2 and 3 of Fig. 1 have been combined into one lens composed of three par-ts, 11, 12 and 13. By a suitablev choice of thekind of glass, that is, With a rather low ratio of .their dispersive powers, the triplet composed of the parts 11, 12 and 13 may bel rendered symmetrical, achromatic and'corrected for spher1cal aberration for conJugate points situated in its anti-principalplanes 9 and 10. The operation o the device of Fig.- 2 is identical with that of Fig.l

l, the field glasses being inserted in ol'der to permit of the shortening of the instrument without reducing its field undesira'bly.

In order to further reduce the length of the instrument while maintaining a proper ment shown in Figs. 3 and 4. In thisdemeans for .erecting the image consisting of a system of reflecting prisms. The device of Fig. 3 has some advantages over the other arrangements, among which are that it is very short in length and because the body of ther instrument is almost invisible to the shooter when his eye is in the firing position. The device of Fig. 3 vconsists of acylindrical section of casing 14 which may be screwed into or otherwise attached to the vbody 15 of the-instrument. lPlaced in the casing 14 is a lensV 16 of'the same construction as that of lens l.' Placed/in the casing 15 is a total reflecting prism/17. Placed in the casingl is also. a second prism 18 which is a combined prism consisting of a combifield of view, I have devised the arrangenation of an Amici prism (or roof prism) and a totally reflecting ordinary prism. `The erecting of the image is produced by the reflection of' the light on the Surfaces meeting along the Ledge E-E, called the roof, which isa well known property of the Amici prism. Secured onto the casing 15 is a casing 19 carrying a lens 20 of the same generalv constructionl as that of the lens 4 (Figs. 1 and 2). ``Located between the prisms 17 and 18 is a plane 21 upon which is engraved or otherwise placed the known image or emblem. The lenses 16 and 20 are so placed that their focal planes are superposed upon the plane 21 between the two prisms i7 and 18, whichyas above stated, carries the known emblem or pattern. f

The prism 17 is held in place by means of a member 22 which has a coil spring 23 around a ,stem 24 attached thereto, "which engages the lower partof the prism and presses the same upward against the member 15. The prism 18 is held in place' against th'ecasing 15 by a similar device.

The means of fastening the variouslenses, &c., in the .casings in the various forms of the deviceshown may be of any well known character and do not form a part ofimy invention. A 4

The mounting of the optical pieces above mentioned {.permits of their adjustnf'ient so that the magnifying power of the complete device is unity for an eye acconunodated to infinity even in the case where the two focal planes are vnot exactly equal. The diaphragms are 'not indispensable and one of the imagel them may receive a polarizing apparatus (analyzer) designed to augment the visibility-of objects when their observation is interfered with by foreign polarized light.

The lines of the known emblem may be coated or .have otherwise applied ,thereto active phosphorescent products by means of radio active' substances which permit employing thev collimator during the night.

Many changes in detail may be made in the carrying out of the principle of my invention, and I therefore', desire to state that I am not to be limited to the exact details shown and described as the same have been used merelv for the purpose of illustrating the principle of my invention.

Having' described my invention, what I claim as new and desire to secure by Letters Patent is;

1. The combination of an ordnance piece with a'sighting device therefor comprising a casing,' lens system having magnifying power of unity and including a known emblem in said casing. and means for erecting member of Said system.

2. In a sighting device for ordnance the combination of a lens, a surface bearing a ransmi-tted through the AfirstA known emblem and located in the focal plane of said lens, and means for erecting the image and transmitting the image and emblem to the eye, said device having unity magnifying power.

3. In a sighting device for ordnance the combination of a casing, two sets of achromatic lenses, the whole having a magnifying power of unity, in said casing, and a member bearing known emblem located in the focal plane of one set of said lenses.

4. In a sighting device for ordnance the combination of a casing, a pair of achromatic lenses in said casing, a member between said lenses bearing a known emblem and means between said lenses for erecting the image transmitted by the first of said lenses said device having unity magnifying power.

5. In a collimating device for sighting with ordnance, the combination of a casing, a pair of lenses therein for projecting an inverted image of a target, a known emblem in the focal plane of the first of said pair of lenses and a second pair of lenses for 'transmitting the said image of said target and said emblem to the eye of the observer and erecting the image of said target, said device having unity magnifying power.

6. In a collimating device for sighting with ordnance, the combination of a casing, a pair of lenses therein for projecting an inverted image of a target, a fieldlens between said pair of lenses and in the focal plane of one of said lenses, a second pair of lenses for inverting said image and a field lens in the focal plane of one of sadsecond pair'of lenses, said device having unity magnifying power.

7. In a collimating device for sighting with ordnance, the combination of a casing, a pair of lenses therein for projectingv an inverted image of a target, a field lens bearing a known emblem and located between said pair of lenses and in the focal plane of one of said lenses, a second pair of lenses for inverting said image and a field lens in the focal plane of one of said second pair of lenses, said device having unity magnifying power. I

8. The method of sighting, which consists in transmitting the image of the target with a known emblem projected on said image through a system of lenses of unity magnifying power and erecting said image of the target. l

In testimony whereof I have signed my name to this specification.

HENRI CHRETIEN. 

